The pupils here_____ all kinds of exercises every day in the past few weeks. 
#104326
A
keptbusydoing
B
keepondoing
C
havekeptbusydoing
D
havebeenkeptbusydoing
推荐题目
Great as Newton was, many of his ideas _______ today and are being modified by the work of scientists of our time.
#102473
A
are to challenge
B
may be challenged
C
have been challenged
D
are challenging
----____your watch? ---Yes, I ___ it when I tidied the drawer
#104819
A
Did you find; have found
B
Did you find;has found
C
Have you found ;found
D
Have you foundl have found